Method of regulating electric generators.



No. 879,887. PATBNTED FEB. 25, 1908. G. S. NEELEY.

METHOD OF REGULATING ELECTRIC GENERATORS.

APPLICATION FILED MAY 9, 1907.

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No. 879,887.. PATE TED FEB. 25, 1908. e. s. NBELBY,

METHOD OF REGULATING ELECTRIO GENERATORS. APPLIOATION FILED MAY 9, 1907.

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GEORGE S. NEELEY, OF ST. LOUIS, MISSOURI.

METHOD OF REGULATING ELECTRIC GENERATORS.

Specification of Letters Patent.

Patented Feb. 25, 1908.

Application filed May 9, 1907. Serial N'c. 372.773.

To all whom it may concern:

Be it known that I, GEORGE S. NEELEY, a citizen of the United States,residing at St. Louis, Missouri, have invented a certain new and usefulImprovement in the Method of Regulating Electric Generators, of whichthe following is a full, clear, and exact description, such as willenable others skilled in the art to which it appertains to make and usethe same, reference being had to the accompanying drawings, forming partof this specification, in which- Figure 1 is a diagrammatic viewillustrating my improved method of regulating an electric generator: andFig. 2 is a similar view illustrating a modified form of regulatingsystem.

This invention relates to a new and useful method of automaticallyregulating the field density of an electric generator, the object beingto maintain a constant voltage in the work circuit or system by a simplearrangement of magnets which control the field resistance bydifferential action.

In the drawings, A indicates an exciter, and B the generator. Theexciter field current passes through wire a to a stationary contact I),then arcs across an air gap to a movable contact 0 suitably pivoted andcarrying an armature d under the influence of the core of a magnet 1.The wire (2 connects the movable contact 0 with magnet 1, the returnwire f from said magnet leading back to the field of the exciter A. rindicates a resistance in series with the field of the generator, whichresistance shunts a current through wires gh through a magnet 2proportional to the strength of the field current of the generator B,and which is also eventually ex actly proportional to the field currentof the exciter A. Magnet 2- is in the form of a solenoid magnet, thecore 2 of which is connected by a spring 2 to the movable contact (37The magnet 1, being in series with the field of the exciter, exerts aninfluence on the armature (Z to increase the length of the are betweenthe stationary contact I) and the movable contact 0, while the magnet 2,be ing energized by the field current of the generator, exerts aninfluence to shorten the distance between contacts Z)-O. Thus themagnets 1 and 2 are in opposition to each other, and, so far as theresistance of the are between the contacts b--c is concerned, it will bemaintained constant at all times by the magnets 1 and 2, as long asthere is no disturbance of the static equilibrium by a change of voltagein the generator B, in which case the force of magnet 3 is affected. Itshould be borne in mind that a rise in the field current of thegenerator B must follow a rise of field current in the exciter fieldwinding and not vice versa. It follows, therefore, as the field currentof the genera tor B must always ultimately be in exact proportion to thefield current of the exciter, that no matter how much exciting currentthe field of the generator B requires the strength of the exciter fieldcurrent will exactly balance it. This feature is new and results inproducing a sensitive yet positive control of the field excitation.

4 indicates a spring whose tension is preferably made adjustable in anysuitable manner, which spring is connected to the upper end of solenoidcore 3*. The purpose of this spring is to yieldingly support the weightof the solenoid cores 3 and 2 so that said cores will be yieldinglysuspended, the spring 4 tending, however, to assist the pull of magnet 2and cause the contact 1. to approach contact Z2. This spring 4 alsoserves as a means for adjusting the regulator to give any desiredinitial line voltage. The action of spring 4 is opposed by magnet 3operating upon a core 3 connected to the core 2 This magnet 3 isenergized by the voltage of the current of the work circuit. Magnet 3 ispreferably in the circuit of the secondary winding 3 whose primary 3 isacross the lighting or work system.

5 is a resistance across the wires a-f, said resistance being preferablyin the form of special incandescent lamps which provide a resistancehaving a negative temperature coeflicient.

hen the exciter is in operation it will be obvious that the fielddensity and voltage of generator B will be regulated by an are formedbetween the contacts t o, which constitutes a variable resistance, theincremerit in which will cause the current to flow through the shunt 5.Thus, conjunctively, the variable resistance and the resistance of theshunt 5 regulate the field density and current output of the exciter A,and thereby directly control the field density and voltage of thegenerator B.

The magnet 2 is energized by the full intensity of the current suppliedto the field of the generator B, or such part of it as may be foundnecessary to use. The magnet 1 is energized by the intensity of thefield current of the exciter A, and is mechanically and magnetically inopposition to the magnet 2.

If a load is thrown on the dynamo B it will increase the intensity ofthe current flowing in the main line wires i7'.

creased it results in a slightly decreased voltage across wires ij whichcorrespondingly weakens magnet 3 then this magnet otters less resistanceto the spring I, and consequentlysaid spring will cause contact 0 tomove toward the contact I). By this action the resistance in the fieldcircuit of the exciter is thus decreased, when the field of thegenerator B will be instantly built up proportionately, and the voltageacross wires 'ij will be consequently raised to unity. The actions ofspring 4 and magnet 3 are reversed when the dynamo is under lull loadand the load begins to decrease. In such an event, the force ol magnet 3becomes the stronger, .due to the slightly increasing voltage, and thusoperates to lengthen the are between the contacts Z2c, increasing theresistance to the field current of the exciter and this compensates forthe decreased load.

My improved regulator will compensate for all ordinary speed variations.It the speed and voltage of the dynamo B is regulated for a givennormal, a decrease of speed acts to decrease the voltage across thewires and as the opposing forces of the magnet 3 and the spring a areequal at normal voltage and speed, a decrease of speed will decrease thevoltage, and consequently the force oi the magnet 3. Spring 4 will thenact automatically to pull the contact 0 toward the contact I), thusreducing the resistance in the field circuit of the exciter as fast asthe speed decreases. If the speed exceeds normal it will also increasethe voltage of the dynamo above normal, and consequently the extra forceof magnet 3 will automatically move the contact a away from the contactZ).

In Fig. 2 I have illustrated the same system that is shown in Fig. 1,except that I have added a magnet 6 energized by the full intensity ofthe current supplied to the system, or such part of it as it may be lound necessary to use, the series or current transiormer L furnishingthe means whereby any proportional part of the current of the workmgcircuit may be utilized, and also as a means for reducing the usual highvoltage. The purpose of this magnet 6 is to take care of line losses,said magnet assisting the act-ion ol the spring 4.

In operation, the contacts I) and 0 never come together, but 011 thecontrary the arc is maintained so as to provide the variable resistancereferred to. Thus the contacts b-c do not constitute a circuit-maker andbreaker as inlnormal operation they are always separater.

When the inteni sity of the current of the working dynamo is in- 1 Ofcourse, in extreme and unusual swear cases a condition might exist inthe system which would cause contacts bc to very closely approach eachother as, for instance, when a full load is suddenly imposed on the workcircuit.

Instead of maintaining the armature (Z, which carries the movablecontact 0, in equilibrium by the opposing forces 01 the mag nets, 1 and2, it is obvious that the armature (Z could be maintained in equilibriumby opposing springs of appropriate sensitiveness. I prefer, however, touse the magnets 1 and 2 because the strength of these magnets varieswith their energizing sources, and consequently the armature (Z, were itnot for disturbing influence of magnet 3 would be held in a position ofstatic equilibrium. The spring 4 and the magnet 3 exert opposing pullswhich influence the balanced armature d, and it is the strength orweakness of magnet 3 which ultimately determines the movement of contact0 toward or away from contact Z) so that the spring 4: and the magnet 3constitute supplemental means tending to maintain the armature (Z in aposition of equilibrium.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

l. The improvement in the art of regulating dynamo electric machinescomprising, in combination, a variable resistance in the field circuitof the exciter, means for ei'l'ectively maintaining the said variableresistance by opposing magnets, one of which is energized by the fieldcurrent of the exciter, and the other by the field current of thegenerator, and means energized by the work circuit or system fordisturbing the balance between said opposing magnets; substantially asdescribed.

2. The improvement in the art of regulating dynamo electricmachineswhich consists in the combination of the field circuit of theexciter and the field circuit of the generator, magnets energized byeach of said circuits respectively, said magnets being opposed to eachother and maintaining in equilibrium between them an arc in series withthe field of the exciter, means energized by the work circuit or systemfor disturbing said equilibrium, said means tending to increase said areand with it the resistance in the field of the exciter, and other meansin opposition to l said last mentioned means, which other means tends todecrease said are; substantially as described.

3. The improvement in the art of regulating dynamo electric machinescomprising a variable resistance in series with the field of theexciter, a shunt resistance 5, which shunt resistance has a negativetemperature coeific ient, opposing magnets for maintaining said variableresistance, said opposing magnets being energized respectively by thefield current of the exciter and by the field current of the generator,mechanical means which tend at all times to decrease said. variableresistance, and magnetic means in opposition to said mechanical means,said magnetic means being energized by the Work circuit of the system.and tending to increase said variable resistance; substantially asdescribed.

4. The improvement in the art of regulating dynamo electric machines,comprising a variable resistance in the field circuit of the excite'r,said variable resistance being controlled by a movable element, incombination with dii'lerential coils for maintaining said. movableelement in a position of equilibrium one of Which coils is energized bvthe field current of the eXciter and the other by the field current ofthe generator, and auxiliary means energized by the Work circuit of thesystem for disturbing the equilibrium established by said difi'erentialcoils; substantially as described.

5. The improvement in the art of regulating dynamo electric machines,the combination With a variable resistance in the field circuit of theexciter, a movable element for varying said resistance, magnetsenergized by the intensities of the field currents of the exciter andthe generator respectively for maintaining said movable element in aposition of equilibrium, and means energized by the current output ofthegenerator for disturbing said equilibrium and for moving said movableelement; substantially as described.

6. The improvement in the art of regulating dynamo electric machinescomprising, in combination, a variable resistance in the form of an arcin the field circuit of the 6X citer, a movable element for varying saidare, magnets energized by the intensities of the field currents of theeXciter and the generator respectively for maintaining said movableelement in a position of equilibrium, means energized by the currentoutput of the generator for disturbing said equilibrium and for movingsaid movable element, and a mechanically yielding force operating toassist the magnet energized by the field current of the dynamo;substantially as described.

In testimony whereof I hereunto afiiX my signature in the presence oftwo Witnesses, this sixth day of May, 1907.

GEORGE S. NEELEY.

Witnesses:

F. R. CORNWALL, LENORE WILSON.

